Solas Regulation 9 - Double bottoms

Discussion in 'Stability' started by Dr34m3r, Feb 18, 2015.

  1. Dr34m3r
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    Dr34m3r Senior Member

    SOLAS , PART B-2, Regulation 9 - Double bottoms in passenger ships and cargo ships other than tankers

    Can anyone explain me how to define the damage zone for a ship having double bottom ( height 1800 mm) ? should i consider only the forward and aft part of the ship ?

    I am using Delftship.
     
  2. Don92
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    Don92 Principal Naval Architect

    Hi! Are you sure that you have to consider this regulation in your case? Generally the damages described under this regulation are only executed where a double bottom has not been fitted or it has been designed under an unusual arrangement.
     
  3. Dr34m3r
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    Dr34m3r Senior Member

    our client want to have perform this calculation to check the survivability after bottom damage.
     
  4. Don92
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    Don92 Principal Naval Architect

    In that case I would define the bottom damage cases to the extent outlined firstly for individual compartments with the damage centre is located at the centre of each compartment. Then I would proceed to define damage cases across two compartments. That should be sufficient.
     
  5. TANSL
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    TANSL Senior Member

    It is very rare that the study of a damage that flooded two compartments is required. Check you if this is necessary because that can make great boats, do not meet the criteria.
    On the other hand, the double bottom height of 1.8 m is probably much greater than the height standards calling for bottom damage.
     
  6. Don92
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    Don92 Principal Naval Architect

    The damage length is however to be considered "at any position along the ships bottom". This surely include damages over two compartments.
     
  7. TANSL
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    TANSL Senior Member

    Let's forget for the moment the damage length, which has nothing to do with what I say. There are several faults that can lead to flooding of two compartments (even with a very small damage length), that is clear and not dependent on any regulation. What I am saying is that, if things have not changed recently, only in very special cases is obliged to study the stability of a vessel with two compartments flooded.
     
  8. Don92
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    Don92 Principal Naval Architect

    I'm not sure I understand your point and I don't mean to offend. I have conducted quite a few damage stability assessments and generally a standard of two compartments is the case both using SOLAS '90 and SOLAS 2009. It is very unlikely the required attained index could be obtained with only consideration of individual compartment damages.
     
  9. TANSL
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    TANSL Senior Member

    Don92, do not offend me at all. We are here to exchange views and, often, regulations are not easy to understand.
    I believe that stability with two flooded compartments is not mandatory for all vessels. I projected a 5 or 6 passenger vessels up to 25 m in length, and have never had to do that study (2 compartments). Probably because of the small length of my boat, the damage length were to disregard.
    I study the stability in the flooded compartments, one by one, and choose the worst case to study, in that case, the wind heeling and passage to a band.
    But I guess you have more experience than me.
     

  10. Don92
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    Don92 Principal Naval Architect

    Ah, I understand where you were coming from now. I was talking generally about much larger vessels. Of course when considering relatively smaller vessels the damage regulation may indeed state only one compartment damage is necessary.
     
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